 |
|
Would you like to test your knowledge on closures ?
Try our exam. Good luck !
|
|
|
Which thread type is recommended to retain a liner without using glue?
- Stripped
Good answer !
A liner can efficiently be retained by a stripped thread.
- Unscrewed
Wrong answer !
Even if an unscrewed thread can retain a liner without glue, the stripped thread does it more efficiently.
|
 |
|
The "T" and "E" dimensions of a bottle are equal to the "T" and "E" dimensions of a closure.
- True
Wrong answer !
The "T" and "E" dimensions on a closure are in line with the bottle's "T" and "E" but they need to be larger. A closure at it's minimum tolerance must fit a bottle at it's maximum tolerance and vice versa.
- False
Good answer !
The "T" and "E" dimensions on a closure are in line with the bottle's "T" and "E" but they need to be larger. A closure at it's minimum tolerance must fit a bottle at it's maximum tolerance and vice versa.
|
|
|
Polystyrene is a resin widely used to produce stripped threaded closures.
- True
Wrong answer !
Polystyrene is too rigid to allow the thread to "strip" during the molding. Polypropylene and polyethylene are the main raw materials used to produce stripped threads.
- False
Good answer !
Polystyrene is too rigid to allow the thread to "strip" during the molding. Polypropylene and polyethylene are the main raw materials used to produce stripped threads.
|
|
|
On a bottling line, we have to check the applied torque while the capper is in use.
- True
Wrong answer !
It is difficult, if not impossible, to measure the applied torque when the capper is in action. It is much easier to verify the immediate removal torque and make a correlation with the long term opening torque. In fact the long term removal torque is the one that counts.
For more information refer to "Torque Application" in the "Closures Technical" section.
- False
Good answer !
It is difficult, if not impossible, to measure the applied torque when the capper is in action. It is much easier to verify the immediate removal torque and make a correlation with the long term opening torque. In fact the long term removal torque is the one that counts. For more information refer to "Torque Application" in the "Closures Technical" section.
|
|
|
Which thread type should you use to retain multiple liners ?
- Stripped thread
Good answer !
In a stripped thread closure, the diameter above the thread ("T") which is the largest dimension in the cap allows the insertion of an oversized liner which will be retained by the threads which correspond to a narrower dimension ("E") and eliminates the need for glue.
- Unscrewed thread
Wrong answer !
Even if it is possible to retain a liner in an unscrewed thread cap, the stripped thread design does it more efficiently.
In an unscrewed thread closure, the diameter above the thread is equal to the "E" dimension, which is the thread to thread diameter and so the wider dimension. Consequently the liner must be slightly smaller than the "E" which forces to use glue to retain the liner inside the closure.
Usually when 2 liners are used (which are not laminated together), the one in the bottom of the cap ensures the secondary sealing and is glued in while the second liner which will offer the primary sealing by either heat induction or pressure sensitive is cut oversized and press-fit inserted between the inside walls (this liner can not be glued inside as it needs to remain on the neck of the bottle). This solution works but with some downfalls. The liners are often wrinkled and a small percentage fall in the boxes during transport.
|
|
|
A stripped closure is of poor quality compared to an unscrewed cap.
- True
Wrong answer !
There is no good or bad thread. Both have different possibilities. It is true that the stripped thread profile is slightly inferior compared to the profile of an unscrewed thread, but it gives solutions to some of the unscrewed thread problems, like the retention of multiple liners, the possibility of having interrupted thread, a wider sealling surface for the liners, ...
- False
Good answer !
There is no good or bad thread. Both have different possibilities. It is true that the stripped thread profile is slightly inferior compared to the profile of an unscrewed thread, but it gives solutions to some of the unscrewed thread problems, like the retention of multiple liners, the possibility of having interrupted thread, a wider sealling surface for the liners, ...
|
|
|
The polymers used to mold closures different than the ones used to mold bottles.
- True
Good answer !
The polymers used for injected molded closures and those used for blow molded bottles come from the same families but have different properties.
For example a polyethylene used for injection molding will have a narrower distribution of its molecular weight than the polyethylene used in blow molding. The outcome is a difference between the physical properties of the objects molded with the two types of polyethylene.
- False
Wrong answer !
The polymers used for injected molded closures and those used for blow molded bottles come from the same families but have different properties.
For example a polyethylene used for injection molding will have a narrower distribution of its molecular weight than the polyethylene used in blow molding. The outcome is a difference between the physical properties of the objects molded with the two types of polyethylene.
|
|
|
The liner's diameter in a stripped thread closure is larger than the one of an unscrewed thread closure.
- True
Good answer !
In a stripped thread closure the diameter above the thread is equal to the dimension "T" as in an unscrewed thread closure the diameter above the thread is equal to the dimension "E" which is smaller than the "T". This explains that the liner in a stripped thread closure has a greater sealing surface.
- False
Wrong answer !
In a stripped thread closure the diameter above the thread is equal to the dimension "T" as in an unscrewed thread closure the diameter above the thread is equal to the dimension "E" which is smaller than the "T". This explains that the liner in a stripped thread closure has a greater sealing surface.
|
|
|
The closures' "S" dimension is equivalent to the "S" dimension of a bottle.
- True
Wrong answer !
In a closure there is no "S" dimension as such.
Note that the bottle's "S" dimension is very important. If it is too tall it might prevent a full turn of thread contact between the bottle and the closure. If it is too small several problems might occur; bad sealing, misalignment of the closure on the bottle, cracking of the top of the closure, ...
- False
Good answer !
In a closure there is no "S" dimension as such.
Note that the bottle's "S" dimension is very important. If it is too tall it might prevent a full turn of thread contact between the bottle and the closure. If it is too small several problems might occur; bad sealing, misalignment of the closure on the bottle, cracking of the top of the closure, ...
|
|
|
The colorant affects the physical characteristics of a plastic closure.
- True
Good answer !
Yes, the colorants have an important influence of the characteristics of a plastic closure.
For example; a red cap will shrink more than a black cap. It will also be less resistant under impact. There are many variations between colours and the types of colorants this is an aspect that molders must master.
- False
Wrong answer !
Yes, the colorants have an important influence of the characteristics of a plastic closure.
For example; a red cap will shrink more than a black cap. It will also be less resistant under impact. There are many variations between colours and the types of colorants this is an aspect that molders must master.
|
|
|
